Decentralized Robust Global Prescribed Performance Control of Unknown Interconnected Nonlinear Systems

This article is concerned with the global prescribed performance control (PPC) problem for the fully interconnected nonlinear systems with nonparametric uncertainties and mismatched disturbances. The allowable state interconnections need only to be continuous, without matching conditions or growth conditions which are widely used in the related works. Moreover, different from the existing global PPC designs, we aim at achieving independent performance specifications for all the errors, whose setting time and accuracy are permitted to be arbitrarily predefined. To this end, a novel decentralized robust global PPC approach is put forward in this article. Herein, heterogeneous tuning functions are skillfully introduced to the PPC design to adjust the errors independently. In addition, a constraint analysis framework based on dialectic by contradiction is established to reveal the inherent robustness of the proposed control against the state interconnections. Two comparative experiments on a coupled tanks apparatus are conducted to demonstrate the theoretical findings.